CVE-2026-88165ImportantFix has a known issueRCENetwork

Windows Active Directory Domain Services Remote Code Execution Vulnerability

MSRC advisory NVD CVE.org

Assessment

Out-of-bounds write in Active Directory Domain Services allows an authorized attacker to execute code over a network.

Severity: Important
CVSS base score: 8.8CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Impact: Remote Code Execution
EPSS, next 30 days: 0.9%Higher than 58% of scored CVEs · FIRST model run 25 Oct 2026 · about EPSS
Public exploit code: No Nuclei template lists it
Exploitability: Exploitation Less Likely
Publicly disclosed: No
Customer action: Required: apply the update
Component: Active Directory Domain Services
Weakness: CWE-787: Out-of-bounds Write
Issued by: Microsoft
Published: 13 Oct 2026 · October 2026
Last revised: 13 Oct 2026

CVSS 3.1 base metricsRed raises the risk · green lowers it

Attack vector: NetworkAV:N
Attack complexity: LowAC:L
Privileges required: LowPR:L
User interaction: NoneUI:N
Scope: UnchangedS:U
Confidentiality: HighC:H
Integrity: HighI:H
Availability: HighA:H

Updates that fix it

10 KBs

KB	Type	Restart	Applies to	Known issues	Other CVEs
KB5126646	Security Update	Required	Windows Server 2025, Windows Server 2025 (Server Core installation)	MitigatedUsers might be unable to sign in to OWA or send emails on Exchange Server	All CVEs in KB5126646
KB5126651	Security Update	Required	Windows 10 Version 1809 for 32-bit Systems, Windows 10 Version 1809 for x64-based Systems, Windows Server 2019 and 1 more	MitigatedUsers might be unable to sign in to OWA or send emails on Exchange Server	All CVEs in KB5126651
KB5126653	Security Update	Required	Windows 11 Version 23H2 for ARM64-based Systems, Windows 11 Version 23H2 for x64-based Systems	None listed	All CVEs in KB5126653
KB5126655	Security Update	Required	Windows Server 2022, Windows Server 2022 (Server Core installation)	MitigatedUsers might be unable to sign in to OWA or send emails on Exchange Server	All CVEs in KB5126655
KB5126657	Security Update	Required	Windows 10 Version 21H2 for 32-bit Systems, Windows 10 Version 21H2 for ARM64-based Systems, Windows 10 Version 21H2 for x64-based Systems and 3 more	None listed	All CVEs in KB5126657
KB5126835	Security Update	Required	Windows Server 2012, Windows Server 2012 (Server Core installation)	None listed	All CVEs in KB5126835
KB5126836	Monthly Rollup	Required	Windows Server 2012 R2, Windows Server 2012 R2 (Server Core installation)	None listed	All CVEs in KB5126836
KB5126868	Security Update	Required	Windows 10 Version 1607 for 32-bit Systems, Windows 10 Version 1607 for x64-based Systems, Windows Server 2016 and 1 more	MitigatedUsers might be unable to sign in to OWA or send emails on Exchange Server	All CVEs in KB5126868
KB5127646	Security Update	Required	Windows 11 Version 26H1 for ARM64-based Systems, Windows 11 version 26H1 for x64-based Systems	None listed	All CVEs in KB5127646
KB5127648	Security Update	Required	Windows 11 Version 24H2 for ARM64-based Systems, Windows 11 Version 24H2 for x64-based Systems, Windows 11 Version 25H2 for ARM64-based Systems and 3 more	None listed	All CVEs in KB5127648

Affected products

ESU, Windows

32 affected products

What changed

First observed 14 Oct 2026

25 Oct 2026 · 17:12:51 UTC EPSS0.9%; scored 24 Oct 2026 → 0.9%; scored 25 Oct 2026
25 Oct 2026 · 01:34:18 UTC EPSS0.9%; scored 23 Oct 2026 → 0.9%; scored 24 Oct 2026
23 Oct 2026 · 15:51:28 UTC EPSS0.9%; scored 22 Oct 2026 → 0.9%; scored 23 Oct 2026
23 Oct 2026 · 09:33:49 UTC Public exploit codeUnknown: exploit-code evidence is incomplete or retained → No Nuclei template listed
23 Oct 2026 · 09:33:49 UTC CISA KEVUnknown: catalog evidence is incomplete or retained → Not listed in the collected catalog
23 Oct 2026 · 09:33:49 UTC Source coverage: public-exploit-codeIncomplete → Current
23 Oct 2026 · 09:33:49 UTC Source coverage: first-epssIncomplete → Current
23 Oct 2026 · 09:33:49 UTC Source coverage: cisa-kevIncomplete → Current
23 Oct 2026 · 09:33:49 UTC Source coverage: msrc-cvrfIncomplete → Current
23 Oct 2026 · 08:31:50 UTC Public exploit codeNo Nuclei template listed → Unknown: exploit-code evidence is incomplete or retained
23 Oct 2026 · 08:31:50 UTC CISA KEVNot listed in the collected catalog → Unknown: catalog evidence is incomplete or retained
23 Oct 2026 · 08:31:50 UTC Source coverage: public-exploit-codeCurrent → Incomplete

Show 12 more recent changes

23 Oct 2026 · 08:31:50 UTCSource coverage: first-epss Current → Incomplete
23 Oct 2026 · 08:31:50 UTCSource coverage: cisa-kev Current → Incomplete
23 Oct 2026 · 08:31:50 UTCSource coverage: msrc-cvrf Current → Incomplete
22 Oct 2026 · 17:33:15 UTCEPSS 0.9%; scored 21 Oct 2026 → 0.9%; scored 22 Oct 2026
21 Oct 2026 · 21:47:24 UTCEPSS 0.9%; scored 20 Oct 2026 → 0.9%; scored 21 Oct 2026
20 Oct 2026 · 20:53:31 UTCEPSS 0.9%; scored 19 Oct 2026 → 0.9%; scored 20 Oct 2026
19 Oct 2026 · 15:12:40 UTCEPSS 0.9%; scored 18 Oct 2026 → 0.9%; scored 19 Oct 2026
18 Oct 2026 · 14:54:30 UTCEPSS 0.9%; scored 16 Oct 2026 → 0.9%; scored 18 Oct 2026
18 Oct 2026 · 14:54:30 UTCLink: October 2026 → /security?release=2026-Oct#cves
16 Oct 2026 · 16:13:25 UTCEPSS 0.9%; scored 15 Oct 2026 → 0.9%; scored 16 Oct 2026
15 Oct 2026 · 21:30:54 UTCEPSS 0.9%; scored 14 Oct 2026 → 0.9%; scored 15 Oct 2026
15 Oct 2026 · 01:07:54 UTCEPSS Not scored → 0.9%; scored 14 Oct 2026

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Collected exploitation and prediction evidence

Risk source coverage

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

cve-program · CVE-2026-88165

Published

Windows Active Directory Domain Services Remote Code Execution Vulnerability

Out-of-bounds write in Active Directory Domain Services allows an authorized attacker to execute code over a network.

Source published: 13 Oct 2026 19:00:12 UTC
Source modified: 25 Oct 2026 18:41:59 UTC
Observed here: 25 Oct 2026 20:02:02 UTC
Source terms: CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

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CVSS 3.1 · 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C